Sweet'N Fat: Artificial sweeteners linked to weight gain
Carl Rance is trying to lose weight, so when he gets thirsty, he normally grabs a diet soda. That may be a bad idea.
Most days, he’ll drink a diet cola while eating lunch out, like he did on a recent Thursday at a Burger King in Harlem, N.Y., and then down more calorie-free Pepsi in the evening, at least four liters a week.
Rance, a 61-year-old diabetic, said he buys calorie-free soda to avoid sugar, but his weight increased from 244 pounds to 256 pounds last month.
“I only eat like this once a day; I eat balanced,” said Rance, waving at the burger and fries in front of him and describing his daily diet of corn flake breakfasts, fruit and nut dinners and zero-calorie soft drinks. “It looks to me,” he said, that the diet soda “is making me gain weight.”
Rance’s wife, Archette, 48, sat across the table, chuckling affectionately. “He’s not losing any weight with diet soda.”
The Rances' suspicion that there may be an odd connection between products with diet sweetener and weight gain just might be true. New research bolsters the counterintuitive feeling that sugar substitutes--like saccharin in coffee, sucralose in low-fat ice cream and aspartame in sugar-free cookies--may do more harm than good to people trying to shed unwanted pounds.
Rats that were fed saccharin-sweetened Dannon yogurt in a Purdue University experiment gained more weight than those given regular yogurt containing glucose, a natural form of sugar. Because the association between sweet taste and high calorie count was broken, it appears the rats’ metabolisms did not speed up when they were fed naturally sweet foods later, resulting in fewer calories burned and overeating.
The research, recently published in Behavioral Neuroscience and directed by Dr. Susan Swithers and Dr. Terry Davidson, is apparently the first to examine the effects of artificial sweeteners outside of soda, and the findings suggest that record obesity rates in America may be tied to high levels of sugar substitute use.
In 1987, fewer than 70 million Americans consumed products containing sugar-free sweeteners, according to the Calorie Control Council, the sugar-substitute industry association. Last year, the number approached 200 million. At the same time, 15 percent of Americans were obese in the late 1980s, according to the Purdue study. Now, that figure has more than doubled.
“Eating foods where sweet taste was not a good predictor of calories may make it harder to regulate food intake and body weight,” said Swithers. “The take-home message is that there can be an assumption that by replacing non-caloric sweeteners, body weight is going to decrease-–that’s not necessarily true.”
Previous studies had linked sweet no-calorie liquids directly to weight gain. Every can or bottle of diet soft drink consumed increased a person’s risk of being overweight by 41 percent, according to a 2005 University of Texas study.
Dr. Adam Drewnowski, an expert affiliated with the Calorie Control Council, dismissed the Purdue study.
“All health experts agree that weight loss is best achieved by a combination of reducing caloric intake, lowering energy density of the diet, and increasing physical activity. By all accounts, low-calorie sweeteners do help,” said Drewnowski., director of the University of Washington’s Center for Public Health Nutrition. “Suggesting that low-calorie sweeteners actually cause people to gain weight is an irresponsible direct application of rat models to dietary counseling and to public health.”
Other scientists said the study was credible, but noted that more research needs to be done for a definitive answer on the value artificial sweeteners.
“The implications could be enormous,” said Dr. Kelly Brownell, director of Yale University’s Rudd Center for Food Policy and Obesity and leading obesity expert. “So many people use these sugar substitutes despite years of controversy; we’re still not sure whether they help or hurt people regulating their weight.”
Whatever the scientific evidence about sugar substitutes, their effect on weight varies widely for Americans across the country.
Linda Sieck, 66, a diabetic from Houston, recently lost 46 pounds by switching to sugar substitutes, exercising and eating balanced meals. She claims to use products such as Sweet’N Low, Splenda and Equal in tea, diet soft drinks and products such as Slim Fast. “I find it hard to believe that it could increase weight–-my appetite always stays the same,” she said.
Molly Schreiber, 42, of Fresno, Calif., said she stopped using zero-calorie products with artificial sweeteners six months ago and since then has lost 85 pounds.
“I was a die-hard, three to five Diet Pepsis per day kinda gal,” she said. “I never realized how much constantly drinking sweet-tasting beverages was increasing my cravings for more sweet foods.”
Lynn Haraldson-Bering, 44, of Clarion, Pa., recently lost 168 pounds and appeared on “The Oprah Winfrey Show.” She doesn’t like artificial sweeteners except for occasionally putting stevia (a naturally sweet herb) in her tea, and doesn’t see a correlation with successful dieting one way or the other.
“My weight gain had nothing to do with sweeteners and my loss definitely happened in spite of them,” she said.
Back in New York, some people simply avoid the sugar substitute debate altogether.
“I don’t mess with that stuff,” said a woman eating lunch at Popeye’s on 125th Street, explaining why she avoided low-calorie sweeteners, including diet soda.
“I just stick to water.”